MSOC - Occlusion Culling for MWSE

MSOC plugin

CPU-side occlusion culling for Morrowind. Each frame the plugin software-rasterizes a coarse depth mask from opaque near-scene geometry, then tests every small NiTriShape leaf against it before the engine draws it. Leaves that fall fully behind the mask are skipped — fewer GPU draw calls, fewer vertex-shader invocations on geometry the player would never have seen.

This is the near-scene half of the work and runs standalone — no extra mods required beyond MWSE.

A distant-statics half is also implemented: the plugin exposes its mask to MGE-XE, which can then skip distant statics that fall fully behind it. The MGE-XE side of this integration is not yet released upstream — the work lives on a development branch and will land in a future MGE-XE release. Until then the plugin's distant-statics path is dormant, and the near-scene culling is what you get.

Hardware notes

Most of the runtime cost lives in two places: software rasterization of near-scene occluders into the mask, and per-occludee TestRect queries on the drain. Both parallelize well on multi-core CPUs via Intel's Masked Software Occlusion Culling threadpool.

• []Modern multi-core CPUs (4+ cores, AVX2 or better): the threadpool amortizes mask-build cost across workers, and the main-thread query path stays cheap. This is where the plugin earns its keep.[/]

  []Older / dual-core CPUs (Sandy / Ivy Bridge era, SSE4. 1 only): the threadpool's wake / flush / suspend overhead per frame outweighs the parallelism win. The plugin auto-detects this on first launch and selects the low-tier preset, which disables the async path entirely and runs rasterization on the main thread. Results on this hardware vary — the plugin may be net-neutral or slightly negative depending on scene density.[/]

  You don't need to think about any of this — hardware tier is detected and applied automatically. The MCM lets you override if needed.

  Requirements

  • []Morrowind (vanilla Morrowind.exe). OpenMW is not supported — the plugin links against MWSE which only targets the original engine.[/]

    []MWSE (recent build). The plugin loads via the MWSE Lua loader.[/]

    []CPU with at least SSE4. 1. AVX2 / AVX-512 paths are auto-selected when available. Fallback path exists below SSE4. 1 but isn't recommended.[/]

    Optional, for the additional distant-statics culling layer:

    []MGE-XE with distant statics rendering enabled.[/]

    [*]MGE-XE build with msoc-plugin integration. This is not yet in any released MGE-XE; the integration lives on a development branch and will be upstreamed in a fut